Heating stoves such as are used in homes have been used for centuries but they never amounted to more than an open fire place used for emergency or a metal box containing a hearth, a charging door and an exhaust leading to a chimney.
The development of the slow combustion type stoves has been plagued with the problem of increased wood tar deposits in the flue ducts. Such deposits eventually catch fire and have been known to consume entire homes and the occupants. One solution to eliminate the chimney fire hazards has been to equip the stove with a catalytic converter which is meant to trap the wood tars and promote more complete combustion thereof. Excessive costs of such catlytists and their containment apart from their dubious performance have not favored wide acceptance of such devices.
Presently the state of the art in the stove heaters has been to add an air jacket around the stove to enhance the efficiency of heat recovery. However, because of space and heat transfer limitations, stoves equipped with air jackets are unable to extract a large portion of recoverable heat which is then lost to the atmosphere.
When analyzing the performance of a heating stove with the aid of heat transfer theory one must realize that a stove with an air jacket is limited in its ability to recover a higher portion of the heat generated by the combustion process. The limiting factor is the overall heat transfer coefficient which is controlled by the velocity of air in the jacket. Also it is difficult to increase the heat transfer area by adding more jacket surface because of space restrictions.